let id = 0;
var items = document.getElementsByClassName('picture');
//向后翻
function clickRight() {
    id = id + 1;
    if (id > 2) {
        id = 0;
    }
    items[id].className = 'show-img picture'
    for (i = 0; i < items.length; i++) {
        if (i !== id) {
            items[i].className = 'hide-img picture'
        }
    }
}
//向前翻
function clickLeft() {
    id = id - 1;
    if (id <0) {
        id = 2;
    }
    items[id].className = 'show-img picture'
    for (i = 0; i < items.length; i++) {
        if (i !== id) {
            items[i].className = 'hide-img picture'
        }
    }
}
